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This forum is for discussions regarding System Infrastructure and Related Equipment. This includes but is not limited to repeaters, base stations, consoles, voters, Voice over IP, system design and implementation, and other related topics.

I've been looking at several options for UHF Trunked Type-II Systems on an economical level and i've come up with some technical questions. This is more for sh!ts and giggles than anything, but given the proper building-top space and if it could be done inexpensively, I would like to try it.

#1) Were there ever any UHF Startsite Desktracs made for use in Startsite systems? I have seen several 800mhz and 900mhz used complete startsite systems for sale online, but no VHF or UHF.

#2) Given the availability of UHF Startsite Desktracs, is there any advantage in retaining their desktrac housing as opposed to directly mounting the individual units in a server case with a power supply feeding all of the units?

#3) If one was able to get their hands on a used MTC3600 Controller and other associated parts from a decommissioned system, how would one go about changing the system parameters (System ID, etc) to what is needed to work with the new hardware?

As far as changing MTC 3600 parameters, that's something that is done back in Schaumburg. They would send you a new codeplug file for the controller that contains the new parameters (System ID, Connect Tone, channel definitions, spacing, etc.) which you would in turn load into the controller via the standard means (Serial + Ethernet Link).

Someone here correct me if I'm wrong, and I probably am, but OBT (other band trunking, meaning non 800/900) didn't really come around until somewhat recently with the exception of the Federal 400MHz systems.

I say this meaning that the DeskTrac product in a trunked format was probably long discontinued before any real VHF/UHF SmartNET/SmartZone systems started getting deployed. I've never seen a trunked UHF mobile before the ASTRO Series came out, though they must clearly exist for the Federal 400MHz stuff.

All the DeskTrac housing really does is provide a power supply and fancy control panel for a MaxTrac radio. There were other options, such as a 2nd radio & controller to make the DeskTrac repeater, as well as a local control and/or tone remote control interface to allow them to be interfaced to consoles and remotes.

Provided you aren't using it as a repeater, there's no reason you can't mount a MaxTrac on a rack shelf with a power supply & external tone remote control interface and end up with exactly the same thing as a DeskTrac base station.

But again, finding trunked MaxTrac radios in VHF/UHF may be impossible.

If you're looking to build a SmartNET system on VHF/UHF, the easiest subscribers to use would probably be ASTRO Spectras. They were available in a consolette configuration much like the DeskTrac.

And if you are asking about StartSite Desktracs in the repeater sense, I can tell you there were never any made for trunked repeater service because there is no way a DeskTrac repeater could ever handle the duties of a control channel, they'd burn up in a matter of hours.

I believe most of the original StartSite repeaters were of the MSF 5000 and MTR 2000 variety.

Again, I'm guessing on a lot of this stuff, so someone please correct me if I'm wrong.

I have actually seen pictures of a Startsite System that had 5 desktrac repeaters at the bottom of the rack, with the controller and telephone interconnect mounted at the top of the rack. I also wondered about the duty cycle issue, but apparently they found some way to make it work in some applications.

In terms of OBT systems, Excel Energy has operated a 450mhz Smartzone system for a while now, but I'm not sure when it entered service or what type of subscriber units they use.

And yes, the goal was to create a UHF Startsite system in the lower 70cm band. I know that it is possible, its just the question of what is the most efficient way to do it.

The major problems thus far have been finding a reasonably-priced controller and a reasonably-priced transmitter combiner and receive multicoupler. That along with the needed experience to put together such a system.

It's still an ongoing project, but it will probably stay on the backburner for a while until the issues are resolved.

Wow... DeskTrac's handling trunked repeater duty. I just can't imagine it. They must have been 2 watt LPI models or something. I just can't fathom how a DeskTrac could survive continuous keydown for control channel duty. Are you CERTAIN they weren't backup/control stations connected to a console somewhere?

Your lower 70cm trunked system idea sounds great to me. I think right now is probably a bad time to try and do it, but the future will offer some excellent opportunities for it.

The reason I say this is that right now, it seems to me that nearly everyone is upgrading to Astro25 systems as funding permits them to. The folks who are upgrading existing SmartNET/SmartZone systems to Astro25 are passing along their older infrastructure to the agencies still using 6809-based hardware.

We're seeing 6809 based hardware showing up in the usual places, but not the MTC 3600 stuff because most of it, in my opinion, is being reused by the folks who are getting rid of their 6809's.

I expect as Astro25 becomes more plentiful and those using the end-line MTC 3600's get the opportunity to upgrade, we'll start seeing MTC 3600's become available.

There is always the other route, which involves setting up a trunked system using Quantars with the IntelliRepeater option enabled, thus allowing you to have a "controllerless" trunking system.

I would think if you could in fact lay hands on a StartSite controller, the most difficult thing would be getting a proper codeplug developed for it.

I've heard rumor that Genesis can program codeplugs for older controllers, but the question is still does the StartSite equipment support OBT, and if so, is 440 supported?

I belive the maximum number of repeaters supported by StartSite is 5, and then you have to upgrade to SmartWorks or SmartNET to get more capacity to a maximum of 28 channels. I think there might be some dispatch console interface limitations as well, I'm not sure.

I remember seeing a device one of my customers had way back when that looked like a Centracom Series II Plus CRT CIE, but had something to do with the trunking system. If I recall correctly, it was some sort of small CIT to handle telephone interconnect on one or two channels, but it did say something about "StartSite" on it. I'll inquire with them as to if they still have it, and exactly what it is.

I've got an *old* Motorola sales catalog that briefly goes over the descriptions and capabilities of the various "small" systems, I should try to dig it out sometime and post the details.

That aside, I would say if you started small (3, maybe 4 at the most channels) you could do it all with proper antenna spacing and standard BpBr duplexers... Anything bigger than that would definitely require multicoupling and combining.

I have actually seen pictures of a Startsite System that had 5 desktrac repeaters at the bottom of the rack, with the controller and telephone interconnect mounted at the top of the rack. I also wondered about the duty cycle issue, but apparently they found some way to make it work in some applications.

In terms of OBT systems, Excel Energy has operated a 450mhz Smartzone system for a while now, but I'm not sure when it entered service or what type of subscriber units they use.

And yes, the goal was to create a UHF Startsite system in the lower 70cm band. I know that it is possible, its just the question of what is the most efficient way to do it.

The major problems thus far have been finding a reasonably-priced controller and a reasonably-priced transmitter combiner and receive multicoupler. That along with the needed experience to put together such a system.

It's still an ongoing project, but it will probably stay on the backburner for a while until the issues are resolved.

What segment of the 'lower' 70CM band are you planning to use?If local usage for links fall in the 420 segment, and don't interfere with link sites on that segment, then okay, but remember the satellite band in the 430 range, that has to be kept free from interference as a satellite's DL signal will be weak, and a repeater on 435.300 will wipe out that bird..Echo (AO-51) has two downlinks on 435.300 and 435.180(iirc).In AZ, we have link systems on 427/429, Etc.... So all is good for the sat folks(myself included).No flames, just an inquiry as to use of the lower segment of 70CM.*I miss UO-14* *sigh*

According to this, it may be inferred that StartSite doesn't have a continuous control channel, nor does it support APCO16 features (Emergency, etc.)

It shows the differences between StartSite, SmartWorks, SmartNET II+, etc.

I've never worked with anything smaller than SmartNET II+ personally...

Startsite can be had in a few different configurations. It is definitely continuous control channel, however it also offers a 'dynamic' option which allows the control channel to become a voice channel if all others are busy. They were used in all bands. I've only heard of the Desktracs being used as repeaters with the Startsite in 800MHz, so I'm unsure of their viability for UHF use. I've only seen MSF5000 & MTR2000 used for UHF.

No trees were harmed in the posting of this message...however an extraordinarily large number of electrons were horribly inconvenienced.

Sure wouldn't mind getting some detailed photos of a StartSite controller (and a SmartWorks for that matter). I'd assume that SmartWorks comes in a standard 6809 card shelf form-factor. As we know, StartSite is in a CCII+ CRT CIE housing (a-la the original DIU being in a T5600 housing). I think the entry level CIT for one or two telco lines was also housed in a CCII+ CRT CIE housing.

Use what you've got, I suppose.

I'd still really like to know what they did to make MaxTrac radios handle trunked repeater service, especially the control channel... They had (another assumption) to be 2-watt units feeding external amplifiers.